/* -*-c-*-
*
- * $Id: rand.c,v 1.1 1999/09/03 08:41:12 mdw Exp $
+ * $Id$
*
* Secure random number generator
*
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: rand.c,v $
- * Revision 1.1 1999/09/03 08:41:12 mdw
- * Initial import.
- *
- */
-
/*----- Header files ------------------------------------------------------*/
+#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <mLib/bits.h>
+#include <mLib/sub.h>
+#include "arena.h"
#include "blowfish-cbc.h"
#include "paranoia.h"
#include "rand.h"
/*----- Static variables --------------------------------------------------*/
-static rand_pool pool; /* Default random pool */
+static const grand_ops gops;
+
+typedef struct gctx {
+ grand r;
+ rand_pool p;
+} gctx;
+
+static gctx *pool = 0; /* Default random pool */
/*----- Macros ------------------------------------------------------------*/
#define RAND_RESOLVE(r) do { \
- if ((r) == RAND_GLOBAL) \
- (r) = &pool; \
+ if ((r) == RAND_GLOBAL) { \
+ if (!pool) \
+ pool = (gctx *)rand_create(); \
+ (r) = &pool->p; \
+ } \
} while (0)
#define TIMER(r) do { \
* Returns: ---
*
* Use: Initializes a randomness pool. The pool doesn't start out
- * very random: that's your job to sort out.
+ * very random: that's your job to sort out. A good suggestion
+ * would be to attach an appropriate noise source and call
+ * @rand_seed@.
*/
void rand_init(rand_pool *r)
r->ibits = r->obits = 0;
r->o = RAND_SECSZ;
r->s = 0;
- rmd160_hmac(&r->k, 0, 0);
+ rmd160_hmacinit(&r->k, 0, 0);
rand_gate(r);
}
r->s = s;
}
+/* --- @rand_seed@ --- *
+ *
+ * Arguments: @rand_pool *r@ = pointer to a randomness pool
+ * @unsigned bits@ = number of bits to ensure
+ *
+ * Returns: ---
+ *
+ * Use: Ensures that there are at least @bits@ good bits of entropy
+ * in the pool. It is recommended that you call this after
+ * initializing a new pool. Requesting @bits > RAND_IBITS@ is
+ * doomed to failure (and is an error).
+ */
+
+void rand_seed(rand_pool *r, unsigned bits)
+{
+ RAND_RESOLVE(r);
+
+ assert(((void)"bits pointlessly large in rand_seed", bits <= RAND_IBITS));
+ assert(((void)"no noise source in rand_seed", r->s));
+
+ while (r->ibits < bits)
+ r->s->getnoise(r);
+ rand_gate(r);
+}
+
/* --- @rand_key@ --- *
*
* Arguments: @rand_pool *r@ = pointer to a randomness pool
void rand_key(rand_pool *r, const void *k, size_t sz)
{
RAND_RESOLVE(r);
- rmd160_hmac(&r->k, k, sz);
+ rmd160_hmacinit(&r->k, k, sz);
}
/* --- @rand_add@ --- *
void rand_add(rand_pool *r, const void *p, size_t sz, unsigned goodbits)
{
const octet *c = p;
- int i, rot, mid;
+ int i, rot;
-#if RAND_POOLSZ != 1279
+#if RAND_POOLSZ != 128
# error Polynomial in rand_add is out of date. Fix it.
#endif
RAND_RESOLVE(r);
- i = r->i; rot = r->irot; mid = i + 418;
- if (mid >= RAND_POOLSZ) mid -= RAND_POOLSZ;
+ i = r->i; rot = r->irot;
while (sz) {
octet o = *c++;
- r->pool[i] ^= (ROL8(o, rot) ^ r->pool[mid]);
+ r->pool[i] ^= (ROL8(o, rot) ^
+ r->pool[(i + 1) % RAND_POOLSZ] ^
+ r->pool[(i + 2) % RAND_POOLSZ] ^
+ r->pool[(i + 7) % RAND_POOLSZ]);
rot = (rot + 5) & 7;
i++; if (i >= RAND_POOLSZ) i -= RAND_POOLSZ;
- mid++; if (mid >= RAND_POOLSZ) mid -= RAND_POOLSZ;
sz--;
}
rmd160_macctx mc;
rmd160_macinit(&mc, &r->k);
- rmd160_mac(&mc, r->pool, sizeof(r->pool));
- rmd160_mac(&mc, r->buf, sizeof(r->buf));
+ rmd160_machash(&mc, r->pool, sizeof(r->pool));
+ rmd160_machash(&mc, r->buf, sizeof(r->buf));
rmd160_macdone(&mc, mac);
BURN(mc);
}
rmd160_macctx mc;
rmd160_macinit(&mc, &r->k);
- rmd160_mac(&mc, r->pool, sizeof(r->pool));
- rmd160_mac(&mc, r->buf, sizeof(r->buf));
+ rmd160_machash(&mc, r->pool, sizeof(r->pool));
+ rmd160_machash(&mc, r->buf, sizeof(r->buf));
rmd160_macdone(&mc, mac);
BURN(mc);
}
*
* Returns: ---
*
- * Use: Gets random data from the pool. The pool's contents can't be
- * determined from the output of this function; nor can the
- * output data be determined from a knowledge of the data input
- * to the pool wihtout also having knowledge of the secret key.
- * If a noise source is attached to the pool in question, it is
- * called to replenish the supply of good bits in the pool;
- * otherwise this call is equivalent to @rand_get@.
+ * Use: Gets random data from the pool, ensuring that there are
+ * enough good bits. This interface isn't recommended: it makes
+ * the generator slow, and doesn't provide much more security
+ * than @rand_get@, assuming you've previously done a
+ * @rand_seed@.
*/
void rand_getgood(rand_pool *r, void *p, size_t sz)
if (chunk * 8 > r->obits) {
if (chunk * 8 > r->ibits + r->obits)
- do r->s->getnoise(r); while (r->ibits + r->obits < 128);
+ do r->s->getnoise(r); while (r->ibits + r->obits < 256);
rand_gate(r);
if (chunk * 8 > r->obits)
chunk = r->obits / 8;
chunk = RAND_BUFSZ - r->o;
memcpy(o, r->buf + r->o, chunk);
+ r->o += chunk;
r->obits -= chunk * 8;
o += chunk;
sz -= chunk;
}
}
+/*----- Generic random number generator interface -------------------------*/
+
+#define GRESOLVE(g, r) do { \
+ if (r != &rand_global) \
+ g = (gctx *)r; \
+ else { \
+ if (!pool) \
+ pool = (gctx *)rand_create(); \
+ g = pool; \
+ } \
+} while (0)
+
+static void gdestroy(grand *r)
+{
+ gctx *g;
+ GRESOLVE(g, r);
+ if (g != pool) {
+ BURN(*g);
+ S_DESTROY(g);
+ }
+}
+
+static int gmisc(grand *r, unsigned op, ...)
+{
+ gctx *g;
+ va_list ap;
+ int rc = 0;
+ va_start(ap, op);
+
+ GRESOLVE(g, r);
+ switch (op) {
+ case GRAND_CHECK:
+ switch (va_arg(ap, unsigned)) {
+ case GRAND_CHECK:
+ case GRAND_SEEDINT:
+ case GRAND_SEEDUINT32:
+ case GRAND_SEEDBLOCK:
+ case GRAND_SEEDRAND:
+ case RAND_GATE:
+ case RAND_STRETCH:
+ case RAND_KEY:
+ case RAND_NOISESRC:
+ case RAND_SEED:
+ case RAND_TIMER:
+ case RAND_GOODBITS:
+ rc = 1;
+ break;
+ default:
+ rc = 0;
+ break;
+ }
+ break;
+ case GRAND_SEEDINT: {
+ unsigned u = va_arg(ap, unsigned);
+ rand_add(&g->p, &u, sizeof(u), sizeof(u));
+ } break;
+ case GRAND_SEEDUINT32: {
+ uint32 i = va_arg(ap, uint32);
+ rand_add(&g->p, &i, sizeof(i), 4);
+ } break;
+ case GRAND_SEEDBLOCK: {
+ const void *p = va_arg(ap, const void *);
+ size_t sz = va_arg(ap, size_t);
+ rand_add(&g->p, p, sz, sz);
+ } break;
+ case GRAND_SEEDRAND: {
+ grand *rr = va_arg(ap, grand *);
+ octet buf[16];
+ rr->ops->fill(rr, buf, sizeof(buf));
+ rand_add(&g->p, buf, sizeof(buf), 8);
+ } break;
+ case RAND_GATE:
+ rand_gate(&g->p);
+ break;
+ case RAND_STRETCH:
+ rand_stretch(&g->p);
+ break;
+ case RAND_KEY: {
+ const void *k = va_arg(ap, const void *);
+ size_t sz = va_arg(ap, size_t);
+ rand_key(&g->p, k, sz);
+ } break;
+ case RAND_NOISESRC:
+ rand_noisesrc(&g->p, va_arg(ap, const rand_source *));
+ break;
+ case RAND_SEED:
+ rand_seed(&g->p, va_arg(ap, unsigned));
+ break;
+ case RAND_TIMER:
+ TIMER(&g->p);
+ break;
+ case RAND_GOODBITS:
+ rc = rand_goodbits(&g->p);
+ break;
+ default:
+ GRAND_BADOP;
+ break;
+ }
+
+ va_end(ap);
+ return (rc);
+}
+
+static octet gbyte(grand *r)
+{
+ gctx *g;
+ octet o;
+ GRESOLVE(g, r);
+ rand_getgood(&g->p, &o, 1);
+ return (o);
+}
+
+static uint32 gword(grand *r)
+{
+ gctx *g;
+ octet b[4];
+ GRESOLVE(g, r);
+ rand_getgood(&g->p, &b, sizeof(b));
+ return (LOAD32(b));
+}
+
+static void gfill(grand *r, void *p, size_t sz)
+{
+ gctx *g;
+ GRESOLVE(g, r);
+ rand_get(&g->p, p, sz);
+}
+
+static const grand_ops gops = {
+ "rand",
+ GRAND_CRYPTO, 0,
+ gmisc, gdestroy,
+ gword, gbyte, gword, grand_range, gfill
+};
+
+grand rand_global = { &gops };
+
+/* --- @rand_create@ --- *
+ *
+ * Arguments: ---
+ *
+ * Returns: Pointer to a generic generator.
+ *
+ * Use: Constructs a generic generator interface over a Catacomb
+ * entropy pool generator.
+ */
+
+grand *rand_create(void)
+{
+ gctx *g = S_CREATE(gctx);
+ g->r.ops = &gops;
+ rand_init(&g->p);
+ return (&g->r);
+}
+
/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff